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2013-08-10 08:57:13

FTDI AJ cable for routers

Most of common modern (dsl) routers run Linux. This offers you many ways for modifications like i.e. enhancements, updates or even to install a linux system of your own. A very handy thing for patching routers is to use a serial console but nearly all routers are "closed" and don't have a serial connector outside. (The classical D-Sub connectors would anyway be too big for small router boxes.)

Most of all routers have an internal serial interface on some pads or pins on the circuit board. The OpenWRT wiki has a nice article on this topic: port.serial. There are two big problems: How do you connect to this internal interface (physically) and what is the best cable or adapter cable to use?

If you have more than one router (i.e. one for dsl, one for WiFi and one replacement router) or you need the serial connection for many customizations then you need a serial connector at the outside of your router. A 3.5mm stereo phone connector is small enough to be built in tiny router boxes. And FTDI has a perfect fitting USB-to-serial adapter cable for this purpose: The TTL-232R-3V3-AJ "audio jack" cable. It is described and shown on their website:

Below are some photos to show you how it looks with this pretty solution. Here are two photos of the widely used TP-Link TL-WR1043ND (click for bigger photos):

WR1043ND back side serial connector WR1043ND inside serial connector

Here's a photo of "hacker's friend" Alfa AP121 (the WiFi Pineapple Mark IV is based on it):

Alfa AP121 back side serial connector

As a last router example here are two photos of the tiny Sempre WLR300-2:

WLR300-2 back side serial connector WLR300-2 inside serial connector

Of course the widely used Raspberry Pi should not be missing:

Raspberry Pi front side serial connector

Update: A 3.5mm jack does also fit in the tiny Hootoo Tripmate Nano (HT-TM02):

Hootoo Tripmate Nano HT-TM02 serial jack

Posted by Frank W. Bergmann | Permanent link | File under: embedded